9. On Lower Marsh street next to Waterloo station there is a grill where you can look down on the Waterloo & City line.

10. If you live near (but not at) the terminus of a line, and you really want a seat, travel the wrong way to the terminus and get back onto a train that is starting there, this time with a guaranteed seat.

(Picture: AP Photo/Lefteris Pitarakis)

11. The steepest gradient on the system that a passenger can travel on is between Bromley-by-Bow and Bow Road, where the gradient reaches 1:28 (or 3.57% in new money).

12. Don’t believe the signs telling you how many steps there are. A lot of them are wrong: the biggest discrepancy being at Belsize Park, where the sign says 219 steps, but there are actually 189.

13. On the new 2015 tube map (with added Overground and TfL Rail services) there are now 408 stations in total, of which only 270 are tube stations – almost exactly two thirds.

(Picture: TfL)

14. There are seven trains in the morning peak on the Hainault to Woodford section (normally as far as they go) that carry straight on into the centre of London.

15. Tube stations operated by Network Rail companies don’t have roundels at them (Richmond, Wimbledon, Upminster, etc) except at Upminster, where there is a lovely old roundel on the signal box at the eastern end of the station.

16. Stay on a terminating Northern line train heading south at Kennington and you’ll go round in a loop, arriving back at Kennington and heading north. People who are drunk/asleep have been known to end up in Edgware, rather than in Morden.